rails-module-one2one

Rails module one to one model.

step to step:

• conditions:

1. A has one B
2. B only belongs to A
3. A是主表，B是从表。
4. A中id的主键值，在B中作为关联用的外键值。
5. 一般来说需要在A、B类中定义对方的引用，以便能够通过一方找到另一方。

• models(ClassRoom/Teacher) :

ClassRoom has one Teacher
Teacher only belongs to ClassRoom.

A: ClassRoom
B: Teacher 

Templates:
rails g model A name:string
rails g B a_id:integer name:string

• create model:

rails g model Teacher class_room_id:integer name:string  
rails g model ClassRoom name:string
rake db:migrate

model class:

# model/class_room.rb
class ClassRoom < ApplicationRecord
  has_one :teacher
end

# model/teacher.rb
class Teacher < ApplicationRecord
  belongs_to :class_room
end


# teacher_controller.rb
private
    def teacher_params
        #列举白名单列表
        params.require(:teacher).permit(:class_room_id, :name )
    end

# class_room_controller.rb
private
    def class_room_params
        #列举白名单列表
        params.require(:class_room).permit(:name )
    end

seed code:

class_room = ClassRoom.create(:name=>'105')  
teacher = Teacher.create(:name=>'xxxx');

teacher.class_room = class_room;

teacher.save
puts teacher.class_room_id;

resources:

• http://blog.csdn.net/abbuggy/article/details/8271963